HOLT Electricians Practice Exam

For motors rated more than 1 horsepower, what is the rated limit of automatic restart after an overload condition?

1. 100 percent

2. 115 percent

3. 125 percent

4. 135 percent

The correct answer is: 125 percent

For motors rated more than 1 horsepower, the limit for automatic restart after an overload condition is set at 125 percent of the motor's rated load. This parameter is important in ensuring that the motor can withstand temporary overloads without causing permanent damage or failure. When a motor experiences an overload situation, it typically causes an increase in temperature and current draw. The ability to restart automatically at this limit allows for the motor to handle moderate overloads while preventing excessive stress that could lead to malfunction. The reason the threshold is specifically set at 125 percent rather than lower values is to accommodate the operational variances that can occur in industrial and commercial settings, where motors may face brief instances of increased load. Systems that allow for a 125 percent restart threshold are engineered to provide a balance between operational flexibility and protection against overheating and damage. Understanding this limit is crucial for electricians and operators to ensure that they select the appropriate overload protection devices and to avoid potential issues related to overheating or unnecessary service interruptions. This parameter supports longevity and reliability in motor operation, making its comprehension essential for effective electrical system management.